Enzyme-linked immunosorbent assay testing of shoots grown in vitro and theuse of immunocapture-reverse transcription-polymerase chain reaction improve the detection of Prunus necrotic ringspot virus in rose

We developed and evaluated two different methods to improve the detection o f the most prevalent virus of rose in Europe, Prunus necrotic ring-spot vir us (PNRSV). Immunocapture-reverse transcription-polymerase chain reaction w as estimated to be about 100 times more sensitive than double-antibody sand wich-enzyme-linked immunosorbent assay (DAS-ELISA) and showed an equivalent specificity. Based on the observation that PNRSV multiplies actively in yo ung growing tissues (axillary shoots and cuttings), an in vitro culture met hod allowing rapid (about 15 days) and homogeneous development of dormant a xillary buds with high virus titers was standardized. ELISA tests of these young shoots showed, in some cases, a 10(4) to 10(5) increase in sensitivit y in comparison to adjacent leaf tissues from the rose mother plants. Betwe en 21 and 98% (depending on the season) more samples were identified as pos itive by using ELISA on samples from shoot tips grown in vitro rather than on leaves collected directly from the PNRSV-infected mother plants. This si mple method of growing shoot tips in vitro improved the confidence in the d etection of PNRSV and eliminated problems in sampling appropriate tissues.